In recent years, a multilayer ceramic capacitor is used in various electronic devices. As a dielectric material for this type of multilayer ceramic capacitor, conventionally, a BaTiO3-based compound allowing a high dielectric constant is widely used. Furthermore, as a material for an internal electrode of such a multilayer ceramic capacitor, a base metal material such as Ni having good conductivity at a low cost is widely used.
For example, Patent Document 1 proposes a barium titanate-based dielectric porcelain composition represented by the composition formula {(Ba1-x-yCaxSry)O}m·TiO2, where 1.005≤m≤1.03, 0.02≤x≤0.22, and 0.05≤y≤0.35.
Further, Patent Document 1 describes a method for producing a multilayer ceramic capacitor, comprising the steps of: producing a green sheet composed of sintered ceramic having a prescribed composition; forming on the ceramic green sheet a conductive layer of nickel, iron, cobalt or an alloy thereof to serve as an internal electrode and stacking such ceramic green sheets in layers; firing the stack at a temperature range of 1200 to 1330° C. in a reducing atmosphere containing 1-5% by volume of hydrogen; and forming at a fired ceramic end surface an external electrode electrically conducting with the internal electrode exposed at the ceramic end surface.
Patent Document 1 describes that a perovskite compound having a portion of Ba substituted with Ca and Sr, respectively, and represented by the general formula AmBO3 has a value of m (=A/B) rendered A-site rich and is fired in a reducing atmosphere allowing a material of the internal electrode to be unoxidized to provide a multilayer ceramic capacitor having a specific resistance of 106 MΩ or more and a dielectric constant ε of 5000 or more.
PTD 1: Japanese Patent Laying-Open No. 55-67567 (see Claims 1 and 2, page 3, Table 1, etc.)